The present invention relates to a process for manufacturing cold-formed shaped forms of packaging from a metal plastic-laminate in which the laminate is held between a retaining tool and a die exhibiting at least one opening, and a stamp is driven into the die opening causing the laminate to be formed into a shaped form of packaging featuring one or more recesses. The present invention relates also to a device for performing the process of cold forming a metal-plastic laminate into a shaped form of packaging.
It is known to manufacture shaped forms of packaging such as e.g. base parts for blister packs, also known as push-through packs, or other forms of packaging e.g. by deep drawing, stretch-drawing or thermoforming. The shaped packaging may be manufactured from thermoplastics or from composites or laminates such as e.g. aluminum foils and plastic films or extruded layers of thermoplastics.
If the packaging is made of laminates containing metal foils, then shaping tools comprising a stamp, a die and a retaining tool may be employed for its manufacture. As it is being deformed, the laminate is clamped securely between the die and the retaining tool, and the stamp moved towards the laminate. As it is lowered, the stamp moves deeper into the openings in the die thereby deforming the laminate. In that process the flat laminate is converted into a shaped part exhibiting one or more recesses which are surrounded by shoulders corresponding to the original flat plane of the laminate. Only that part of the laminate in the region of the die opening can flow or be stretched to form a shaped part. Adequate lateral distance must be maintained between the stamp and the die opening in order that the laminate, especially laminates containing metal foil, can be deformed without cracks and pores forming. If the laminate contains a metal foil, only recesses of small sidewall height can be achieved by this cold forming process. The result is poor drawing ratios i.e. shallow recesses of large diameter and, therefore, forms of packaging which are too large in relation to the contents.
One possibility for obtaining more laminate for shape-forming purposes may be to reduce the retaining force and to employ deep drawing methods. However, folds would form in the edge or shoulder regions, and so this type of technology may not be used e.g. for making blister packs from laminates containing metal foil. The edge region and, if desired, the shoulder region of shaped forms of packaging are normally employed for sealing on the lid. If there were folds present there, however, then it would not be possible to seal the edge and shoulders.